Determining reference data for overnight oximetry in neonates: A pilot study.

OBJECTIVE: To determine the variability of overnight oximetry parameters in a group of normal, healthy term infants; to enable the calculation of the number of subjects required to produce reliable reference ranges for neonatal overnight oximetry. METHODS: A convenience sample of normal, healthy term neonates was recruited. Each had overnight oximetry using the Masimo SET Radical oximeter (data downloaded using Profox software). The report included the number of oxygen desaturation events (an absolute decrease in SpO2 of 4 or more), and the duration of oxygen saturations <90%. RESULTS: 21 babies were recruited with data available from 19. 32% were female; 68% born by vaginal delivery; 37% fully breast feeding, 53% bottle and 11% by a combination of both. The mean (SD) GA was 39.2 (0.79) weeks, the mean (SD) BW was 3477 (240) grams. The median (IQR) post-natal age at the time the oximetry recording started was 31 (28-41) hours; four babies were <24 h old. All babies had some desaturation events ranging from 4 to 36 times per hour. On average babies spent 3.0% (SD 2.3) of the time with an SpO2 < 90% (range 0.12-7.94). CONCLUSIONS: In a cohort of healthy term neonates, as assessed by overnight oximetry, the mean SpO2 was 97% (SD 1, range 95-99). All neonates had a number of oxygen desaturation events ranging from 4 to 36 per hour. The mean proportion of time spent with oxygen saturations below 90% was around 3%.

Neonatal early-onset sepsis calculator safety in an Australian tertiary perinatal centre.

AIM: To determine if any cases of culture-positive neonatal early-onset sepsis (EOS) would be missed using the neonatal EOS calculator, when compared with current guidelines and practices. METHODS: Retrospective audit of all neonates born at ≥35 weeks and admitted to Royal Brisbane and Women's Hospital with EOS from January 2014 to December 2020. A missed case was defined as antibiotic therapy not being recommended within 24 h of birth. Management recommendations according to the neonatal EOS calculator were compared with current guidelines and current practices. RESULTS: There were significantly more missed cases using the neonatal EOS calculator compared to the current guideline and current management groups. Using the neonatal EOS calculator, 11 neonates (35%, 95% confidence interval 19.2-54.6%) would not have received antibiotics by 24 h of age. In comparison, only one neonate (3%, 95% confidence interval 0.1-16.7%) would not have received antibiotics by 24 h of age using the current guidelines. In terms of the current practice in the cohort of patients, two neonates (6%) did not receive antibiotics by 24 h of age. CONCLUSIONS: The significantly higher rate of missed cases using the neonatal EOS calculator compared with current guidelines and practice supports the concerns many neonatologists have regarding safety of the neonatal EOS calculator.

Gentamicin Dosing in Neonates with Normal Renal Function: Trough and Peak Levels.

BACKGROUND AND OBJECTIVE: Gentamicin is commonly used in neonates, and it requires drug concentration monitoring. The objective of this study was to determine the extent of high trough (≥ 2 mg/l) and therapeutic peak serum gentamicin concentrations (5-12 mg/l) using our current gentamicin regimen and to adjust the dosing regimen accordingly and reassess. METHODS: This was a prospective cohort study of neonates, with normal renal function, who were prescribed gentamicin. Group 1: March 2014-July 2017-gentamicin intravenous (IV) 2.5 mg/kg given every 36 h if < 30 weeks gestational age (GA) and every 24 h if ≥ 30 weeks GA; Group 2: August 2019-February 2020-gentamicin IV 3.5 mg/kg given every 36 h if < 30 weeks GA and every 24 h if ≥ 30 weeks GA. We assessed the number of neonates with aberrant trough and peak serum gentamicin concentrations. RESULTS: Forty-eight neonates < 30 weeks GA and 34 ≥ 30 weeks GA were given 2.5 mg/kg gentamicin. Eleven (23%) neonates < 30 weeks GA and four (13%) ≥ 30 weeks GA had subtherapeutic peak concentrations (< 5 mg/l); none had supratherapeutic (> 12 mg/l) or toxic trough concentrations (≥ 2 mg/l). Forty-four neonates < 30 weeks GA and 54 ≥ 30 weeks GA were given 3.5 mg/kg gentamicin. Eighty-four (86%) had non-toxic trough concentrations (< 2 mg/l). One (1%) < 30 weeks GA neonate had subtherapeutic (< 5 mg/l) and one (1%) neonate ≥ 30 weeks GA had supratherapeutic (> 12 mg/l) peak concentrations. CONCLUSIONS: Gentamicin regimen of 2.5 mg/kg given every 36 h for neonates < 30 weeks GA and every 24 h for neonates ≥ 30 weeks GA was suboptimal at achieving therapeutic gentamicin peak. Increasing the dosage to 3.5 mg/kg achieved therapeutic peak concentrations in 98% and non-toxic trough concentrations in 86% of all neonates (prior to dose interval adjustment).

Weight gain in the first week of life and its association with morbidity and mortality in extremely low birthweight (ELBW) infants.

BACKGROUND: Weight gain in the first week of life is indicative of fluid excess in preterm neonates. AIMS: To determine if morbidity and/or mortality of extremely low birthweight (ELBW) infants was lower in those who did not have excess weight gain in the first week of life, compared with those who did. STUDY DESIGN: Retrospective cohort study. SUBJECTS: ELBW infants born from 1st May 2014 - 31st May 2019. EXCLUSIONS: major congenital abnormalities (including hydrops), died within the first 7 days, no recorded weight on day 6, 7 or 8. OUTCOME MEASURES: We compared infants whose weight was greater than birthweight by day 7 and infants whose weight remained at, or below, birthweight by day 7. RESULTS: There were 312 ELBW infants in the study population: 15 (5%) died before discharge from hospital. Holding birthweight and gestational age (GA) constant, the odds of death in neonates with day 7 weight >birthweight was about 3 times the odds of death in neonates with day 7 weight ≤birthweight (adjusted odds ratio 3.18, 95% confidence interval 0.66-15.26, p = 0.15). Neonates with day 7 weight >birthweight were more likely to have had a PDA that required treatment than those with day 7 weight ≤birthweight (65% versus 43% respectively; p <0.001). CONCLUSIONS: ELBW infants who gain weight in the first week of postnatal life, have a greater risk of PDA requiring treatment and may have a higher risk of mortality than infants who lose weight in the first week of life.

Ventilation settings in preterm neonates with ventilator-dependant, evolving bronchopulmonary dysplasia.

OBJECTIVE: The only guidance in the literature on which tidal volumes to use when ventilating babies with, or at high risk of, bronchopulmonary dysplasia (BPD) suggests using very large volume breaths of around 8-12 mL/kg and low rates (10-20 breaths per min) to achieve adequate gas exchange, whilst acknowledging there are no data to validate these strategies. The aim of this retrospective, observational, cohort study was to identify the mechanical ventilation settings that are used, and what carbon dioxide (CO2) levels were achieved, in neonates with ventilator-dependant evolving BPD. METHODS: This retrospective cohort study included neonates born <30 weeks GA admitted to the Grantley Stable Neonatal Unit between May 2014 and December 2018. Included ventilator-dependant neonates with evolving BPD ventilated on either or all days 28, 42 and 56 of life. RESULTS: A total of 105 neonates were included, all were between 23 and 28.5 weeks GA. The median (IQR) GA was 25.1 (24.2-26.5) weeks and BW 708 (608-809) grams. Neonates who required conventional mechanical ventilation (CMV) at each of the three time-points had median tidal volumes ranging between 4.5 and 4.7 mL/kg, median ventilator rates of 35-50 and MAPs of 10-11 cmH2O. For those neonates requiring HFOV, median MAPs ranged from 14 to 18 cmH2O and tidal volumes from 1.4 to 2.2 mL/kg to achieve adequate ventilation and oxygenation. CONCLUSIONS: Neonates with ventilator-dependant evolving BPD were ventilated either with CMV using tidal volumes of around 4-5 mL/kg, or HFOV using tidal volumes around 1-2 mL/kg, which achieves adequate ventilation and blood gas results.

NeoSTRESS: Study of Transfer and Retrieval Environmental StressorS upon neonates via a smartphone application - Sound.

AIM: This study aimed to measure sound exposure during neonatal retrieval, determine whether this varied with mode of transport, and compare noise exposure to recommended levels in neonatal intensive care units. We also aimed to assess the acceptability of using a smartphone application to measure sound. SETTING: Neonatal retrieval service in Brisbane, Australia. METHODS: The Physics Toolbox Sensor Suite application was installed on a Samsung Galaxy S5 smartphone and calibrated for sound measurement. Data were collected during outbound, non-patient legs of 45 retrievals - 25 road, 11 fixed wing aircraft and 9 rotary aircraft journeys. Data were saved to cloud storage, then analysed using PostgreSQL database. RESULTS: The median sound level was 83 dB (interquartile range 66-91; range 27-≥97 dB). Continuous equivalent sound (Leq ) was 90 dB across all journeys. Rotary transport was loudest (Leq 94 dB). Fixed wing (Leq 89 dB) and road (Leq 87 dB) journeys also resulted in significant sound exposure. Sound exceeded recommended levels (45 dB) for 99% of all journey time, regardless of the mode of transport. CONCLUSIONS: Neonates encounter harmful sound levels during retrieval - louder than recommended levels for 99% of all retrieval time. Sounds levels were highest in rotary aircraft transport compared to fixed wing or road transport. It is feasible to use a calibrated smartphone application instead of a sound metre.

Bacterial colonisation of the endotracheal tube in ventilated very preterm neonates: A retrospective cohort study.

AIM: To determine the rate, type and timing of bacterial endotracheal tube (ETT) colonisation in neonates born <32 weeks gestational age (GA); and if bacterial colonisation is associated with chronic lung disease (CLD), septicaemia, length-of-stay or mortality. METHODS: All intubated newborns born <32 weeks GA were included. Endotracheal aspirates were routinely obtained three times-per-week. Cohort was divided into three colonisation groups: no growth, normal respiratory flora only, significant bacteria. Logistic regression was performed to identify if ETT bacterial colonisation was associated with CLD, septicaemia or mortality. A general linear model was fitted for length-of-stay. RESULTS: ETT aspirates were sent from 1054 infants: no growth n = 319, only normal respiratory flora n = 357, and significant bacteria n = 378. ETTs became colonised in 70%, most in the first week of life (82%). Most grew normal respiratory flora (642 infants). In those with significant bacteria, 40% grew Gram-negative species; Klebsiella in 34%. Staphylococcus aureus grew in 104 patients. Adjusted odds ratios for CLD (43% of cohort) compared with no growth were, for normal respiratory flora, 0.58 (95% confidence interval (CI) 0.34-0.99) and, for significant bacteria, 0.48 (95% CI 0.24-0.93). With no overall association between colonisation group and CLD in the adjusted model P = 0.07. The odds of septicaemia (10% of cohort) were 4.50 (95% CI 1.98-10.23, P < 0.001) times greater for significant bacteria compared with no growth. No significant associated was found with mortality or length-of-stay. CONCLUSIONS: Bacterial colonisation of ETTs is common. It is associated with more septicaemia. There was no significant association with CLD, longer admission or mortality.

NeoSTRESS: Study of Transfer and Retrieval Environmental StressorS Upon Neonates via a Smartphone Application-Light.

OBJECTIVE: This study aimed to measure the light levels neonates would be exposed to during retrieval, determine whether this varied with transport mode, and compare them with recommended light exposure in neonatal intensive care units. We also aimed to determine the ease of use and acceptability of using the smartphone application. SETTING: A neonatal retrieval service in Brisbane, Australia. METHODS: This prospective study used the calibrated smartphone application Physics Toolbox Sensor Suite (Vieyra Software, Washington, DC). Data were collected during the outbound, nonpatient leg of 45 retrievals (25 road, 11 fixed wing aircraft, and 9 rotary aircraft journeys). Data were saved to Cloud storage and then analyzed using the PostgreSQL database. RESULTS: The median illuminance was 6 lux (interquartile range [IQR], 1-58). The maximum recorded was 93,842 lux. The median illuminance during daytime journeys was 15 lux (IQR, 2-77). The median light level for night journeys was 1 lux (IQR, 0.5-8). Illuminance exceeded the recommended level (600 lux) for 2.1% of all journey time. CONCLUSION: Retrieved neonates can be exposed to light in excess of recommended neonatal intensive care unit levels, including extremely bright light. It is feasible, with good staff acceptability, for a calibrated smartphone application to be used in place of a light meter.

Does earlier arrival of the retrieval team improve short-term outcomes in outborn extremely premature infants?

AIM: The risk of mortality and morbidity is increased in outborn, extremely premature infants. We aim to determine whether earlier arrival of the retrieval team after the birth of infants less than 29 weeks gestation improves short-term mortality and morbidity. METHODS: This is a retrospective analysis of a cohort of infants less than 29 weeks gestation who were retrieved to the Royal Brisbane and Women's Hospital (RBWH) over a 5-year period. Demographic information regarding the infant and mother, retrieval team arrival time and outcome data was collected. Primary outcomes investigated were mortality prior to discharge from hospital or a composite of mortality or severe intraventricular haemorrhage (IVH). RESULTS: Data on 105 infants were analysed; 88 infants (83.8%) survived to discharge home, and 79 (75.2%) survived to discharge without severe IVH. On univariate analysis, there was no significant association between age at arrival of the retrieval team and death prior to discharge (P = 0.94) or death prior to discharge or severe IVH (P = 0.83). On logistic regression analysis, age at arrival of retrieval team remained non-significant for a reduction in death prior to discharge and composite of death or severe IVH (P = 0.70 and P = 0.99, respectively). CONCLUSION: The earlier arrival of the retrieval team is not associated with improved short-term outcomes in outborn, extremely preterm infants who are retrieved and admitted to a tertiary neonatal intensive care unit - for infants where the retrieval team arrived within about 8 h of birth.

The availability of probiotics and donor human milk is associated with improved survival in very preterm infants.

BACKGROUND: To determine whether the introduction of pasteurized donor human milk and probiotics for infants born < 32 weeks gestational age or < 1500 g birthweight is associated with a reduction in mortality and the incidence of necrotising enterocolitis (NEC) and sepsis. METHODS: We performed a retrospective analysis of two cohorts: before and after the introduction of probiotics and pasteurised donor human milk. Univariate analysis of primary and secondary outcomes was performed; variables impacting outcomes were assessed using multivariate logistic regression. RESULTS: There were 1791 infants: 1334 in the pre-donor milk/probiotic cohort and 457 in the post-donor milk/probiotic cohort. On univariate analysis, mortality (7.6 vs. 2.4%, P < 0.001) and incidence of sepsis (6.2 vs. 3.5%, P = 0.028) were statistically significantly lower in the post-donor milk/probiotic group. NEC (2.8 vs. 1.5%, P = 0.14) and non-NEC associated gastrointestinal perforation (1.6 vs. 0.4%, P = 0.052) were lower in the post-donor milk/probiotics cohort, but these were not statistically significant. The difference in mortality remained statistically significant on multivariate analysis in the post-donor milk/probiotic cohort compared to those in the pre-donor milk/probiotic cohort (odds ratio 0.31, 95% confidence interval 0.16-0.61). The decrease in the incidence of NEC was consistent with previous observational studies but the difference was not statistically significant. CONCLUSION: The availability of probiotics and pasteurised donor human milk is associated with a reduction in mortality in very preterm infants.

The use of overnight oximetry in neonates: A literature review.

There is much debate between neonatologists and paediatricians about appropriate oxygen saturation targets for babies with chronic neonatal lung disease (CNLD). Overnight oximetry is used to guide the fraction of inspired oxygen to use. We did this literature review to examine the current literature on the use of overnight oximetry in term infants, preterm infants and babies with CNLD (especially relevant to ex-preterm babies with CNLD going home on oxygen). We reviewed the literature from January 1990 to October 2017 by searching the following databases: Cochrane Central Register of Controlled Trials, The Joanna Briggs Institute, CINAHL, MEDLINE, Scopus, EMBASE, ProQuest and Science Direct. Sixteen articles were included in the review. The literature available on overnight oximetry in neonates is limited, it is not contemporary, and it reports studies that did not use oximeters with modern software for data collection and analysis. It is imperative that reference ranges be defined for overnight oximetry parameters so that babies are not inadvertently administered inappropriate amounts of oxygen.

Factors associated with infants receiving their mother's own breast milk on discharge from hospital in a unit where pasteurised donor human milk is available.

AIM: To determine the proportion of very preterm infants who were exclusively fed breast milk at the time of discharge home, before and after the availability of pasteurised donor human milk (PDHM). METHODS: This was an observational retrospective cohort study with historical comparison, comparing two cohorts (<32 weeks gestational age or very low birthweight) before and after the availability of donor human milk. The main explanatory variable was the PDHM cohort: pre-PDHM or post-PDHM. The primary dichotomous outcome variable was defined as whether the baby was being fed with breast milk only at the time of discharge home, compared with those fed with artificial formula alone or mixed feeding (artificial formula and breast milk). RESULTS: There were 1088 babies in the pre-PDHM cohort and 330 in the post-PDHM cohort (total n = 1418). Following the introduction of PDHM, 56% (185/330) were exclusively fed breast milk at the time of hospital discharge and 57% (620/1088) in the pre-PDHM cohort. The availability of PDHM is not a significant predictor of feeding outcome upon discharge (P = 0.45) when adjusted for maternal age, log-transformed post-natal age at discharge home and any congenital abnormality. CONCLUSIONS: The availability of donor human milk in our unit is not associated with a decrease in the number of very preterm infants receiving mother's own breast milk at time of discharge home. Other factors that positively impact the successful establishment of breastfeeding in preterm babies were older maternal age, the absence of any congenital abnormality and a shorter duration of hospital stay.

Study of movement of umbilical venous catheters over time.

AIM: To quantify, in well-positioned umbilical venous catheters (UVC), the direction and magnitude of catheter tip migration. METHODS: In this prospective, single-centre, observational, cohort study, infants with a UVC inserted that reached the target zone - inferior vena cava, from ductus venosus to cavoatrial junction (CAJ) - were included. Ultrasound was used to position the catheter tip as near to the CAJ as possible at insertion and to guide any subsequent withdrawals of the catheter. Radiographs and ultrasound were repeated the day following the insertion of the UVC and on any day following adjustment. A final scan was performed on the day of catheter removal. The anatomical position of the catheter and its distance from the CAJ was recorded with each scan. RESULTS: The study ran from May 2015 to August 2016 in the neonatal unit at the Royal Brisbane and Women's Hospital. Thirty-eight patients were recruited, but 18 failed to negotiate the ductus venosus. For the remaining 20, the initial UVC position was within 3 mm of the CAJ on ultrasound. Subsequently, on day 2, 25% of catheters were well positioned, 65% were high and 10% were below the target zone. On the late scan prior to UVC removal, 90% of catheters had migrated from their position on the preceding scan: outward migration in 80% of cases ranging from 2 to 23 mm (median 8.5 mm). Only 35% of catheters remained well positioned. CONCLUSION: The majority of UVCs migrate over time, usually inwards initially and then outwards to a low position.